Heating system and method of heating for an inhaler device

ABSTRACT

A heating system for an inhaler device, such as an e-cigarette or a personal vaporizer, for generating an aerosol and/or a vapor from a substance to be heated includes at least one supply channel for conveying a substance to be heated, especially a liquid solution or a gel, from a supply reservoir by or under capillary action or surface tension forces, and a heater configured to heat the substance as it is conveyed through the at least one channel.

FIELD OF THE INVENTION

The present invention relates to an inhaler device, such as anelectronic cigarette (e-cigarette), a personal vaporizer or anelectronic vapor delivery system. More particularly, the inventionrelates to a heating system for such an inhaler device and a method ofheating for generating an aerosol and/or a vapor from a substance to beheated in such a device.

BACKGROUND OF THE INVENTION

Inhaler devices of the above types, namely e-cigarettes and personalvaporizers and electronic vapor delivery systems, are proposed as analternative to traditional smoking articles, such as cigarettes,cigarillos, cigars and the like. Typically, these inhaler devices aredesigned to heat a liquid solution or a gel to produce or generate anaerosol and/or a vapor to be inhaled by a user. This liquid or gel isusually a solution of propylene glycol (PG) and/or vegetable glycerin(VG), and typically contains a flavorant or one or more concentratedflavors.

Despite the increasing demand for these inhaler devices and the growingmarket, efforts are still required to develop the performance of thesedevices, with a view to offering more efficient and improved products.For example, these efforts are directed to an improved aerosol and/orvapor generation, improved aerosol and/or vapor delivery, and moreefficient use of energy in aerosol and/or vapor generation to improvethe energy consumption, e.g. to enhance the battery life of the device.

SUMMARY OF THE INVENTION

In view of the above, one idea of the present invention is to provide animproved inhaler device, and more particularly an improved heatingsystem and heating method for generating aerosol and/or vapor from asubstance in an inhaler device.

According to one aspect, therefore, the invention provides a heatingsystem for an inhaler device, such as an e-cigarette or a personalvaporizer, for generating an aerosol and/or a vapor from a substance tobe heated, the system comprising:

-   -   at least one supply channel for conveying a substance to be        heated, especially a liquid solution or gel, from a supply        reservoir by capillary action or by surface tension forces        within the at least one channel; and    -   one or more heater or heating means configured to heat the        substance as it passes, or is conveyed, through the at least one        channel.

In this way, the invention provides a heating system with which heatingof the substance, such as a liquid solution or gel, may be performed orcarried out in a distributed manner in the individual supply channelsfor conveying that liquid or gel substance. Each supply channel thustypically provides a narrow passage or a capillary passage forgenerating the capillary action or the surface tension forces thatconvey/s or transport/s the substance along and within each channel. Inthis regard, each said at least one channel is preferably in the form ofa bore or tube providing a capillary passage for flow of the substanceto be heated.

Thus, in some embodiments of the invention, the heating system comprisesa plurality of supply channels for conveying the substance to be heatedunder capillary action or surface tension forces, and the heating meansis configured to heat the substance as it is conveyed through eachsupply channel. The at least one supply channel with the one or moreheater or heating means may define or form at least a first heating zonefor the substance to be heated. The plurality of supply channels and theheating means may therefore together define the first heating zone forthe substance to be heated.

In some embodiments of the invention, the heating means comprises atleast one first heating element that is provided within the at least onesupply channel. In this regard, the first heating element desirablyextends along a length of the supply channel. The at least one firstheating element may be an electrical heating element for Joule heatingor resistance heating. To this end, each first heating element mayinclude one or more of an electrically conductive wire, strip, foil, orconductive coating in the at least one supply channel. For example, sucha foil or conductive coating may preferably form a layer or coating onan inner surface of each supply channel. The heating elements preferablycomprise a material selected from the group of Nichrome 80/20,Cupronickel (CuNi) alloys, Kanthal (FeCrAl), and molybdenum silicide(MoSi₂). Furthermore, the heating elements are desirably powered by anelectrical supply, such as a battery, in the inhaler device.

In some embodiments, the heating system of the present inventioncomprises a housing that accommodates the supply reservoir for thesubstance to be heated, and a body member that separates the supplyreservoir from a vapor chamber and provides fluid communicationthere-between via the at least one supply channel. With this heatingsystem in an inhaler device, e.g. an e-cigarette or personal vaporizer,a user can then inhale an aerosol and/or vapor formed from by heating ofthe substance from the vapor chamber. Preferably, the at least onesupply channel is formed in a periphery of and/or through the bodymember. Accordingly, each of the first heating elements is alsopreferably provided in or on the body member. The first heating elementsmay also be interconnected by electrically conductive bridges in or onsaid body member.

In this way, the supply channels in or on the body member having the oneor more heater or heating means for heating the substance as it passesor is conveyed through those supply channels may together form a (first)heating zone for the substance to be heated. Furthermore, as the bodymember preferably separates the supply reservoir from a main (second)heating zone for vaporization of the substance (i.e. liquid solution orgel), each supply channel is thus typically configured to convey ortransport the substance from the supply reservoir to the main (second)heating zone. In this way, the (first) heating zone of the supplychannels may serve to preheat and expand the substance only. Thepreheated substance is therefore able to migrate to the second heatingzone after preheating. That is, the preheated substance may begin toboil or vaporize in the first heating zone and expands (e.g. as vapor,thermally expanding liquid, or discrete liquid droplets) along the oneor more channels into the second heating zone.

In some embodiments, the body member is comprised of an electricallyinsulating material. The supply channels are advantageously formed asfine or narrow bores or capillary passages having a diameter in therange of 0.1 to 2.0 mm, and preferably in the range of 0.1 to 1.0 mm,i.e. small and precisely dimensioned. The body member nay also be formedof a material that may be machined or manufactured with precision. Aceramic material may be chosen for the body member, as it may satisfyboth of the requirements, as well as being very temperature resistant.Other materials, such as polymer plastics, silicates, or similarmaterials may also be contemplated, however.

In some embodiments, therefore, a main (i.e. second) heating zone may beprovided as a single chamber or cavity within the housing of the system,and each supply channel is provided in fluid communication therewith. Inan alternative embodiment, however, the second heating zone may includea number of second heating cavities, with at least one supply channel influid communication with a respective one of the second heatingcavities. The main or second heating zone preferably includes at leastone second heating element, which may again be an electrical element,such as a wire, ribbon, strip, foil, or conductive coating for Jouleheating or resistance heating. Such a wire or coil may extend througheach second heating cavity. In the case of a foil or coating, however,this may be provided as a film deposit or lining on a surface of eachsecond heating cavity.

In this way, the heating system of the invention may provide two-stageheating for the inhaler device. An initial heating or “preheating” ofthe substance (e.g. liquid or gel) occurs in the first heating zone,i.e. in the supply channels of the body member separating the supplyreservoir from the main or second heating zone. Here the substance maybe subject to pressurization, possibly even boil and partially vaporize,and will typically undergo a thermal expansion. The thermal expansionmay generate a localized pressure increase in the first heating zone,which then forces or drives the substance under pressure towards thesecond heating zone. In such a case, the substance may be comprised ofan aerosol, droplets, and/or suspension of the liquid solution or gel tobe heated and/or a vapor thereof. The substance is further vaporized inthe second heating zone and undergoes a volumetric expansion during thephase change to gas. Each second heating cavity may communicate with atleast one nozzle for delivery of the vapor and/or aerosol produced to amouthpiece of the inhaler device. Thus, due to the preheating, theheating required to carry out full vaporization of the substance in thesecond heating zone can be achieved both quickly and efficiently.

In some embodiments, the first heating zone or supply channels mayreceive the substance to be heated (e.g. liquid or gel) from the supplyreservoir via a feed mechanism. The feed mechanism may include one ormore of capillary action and pressure bias. A pressure bias may becreated by applying pressure to the liquid or gel substance stored inthe supply reservoir, such that it is biased from the reservoir towardsthe first heating zone or supply channels. Alternatively, or inaddition, the supply reservoir may be flexible or collapsible forapplying a pressure bias, and/or may include a vent such that suctionand capillary action create a pressure bias between the reservoir andthe supply channels promoting migration of the substance. Furthermore,the feed mechanism may be configured to vary a feed rate of thesubstance from the supply reservoir. To this end, the feed mechanism ofthe heating system may include a valve mechanism to regulate the feedrate of the substance. The feed rate may be set or adjusted by a user tomatch or suit an inhalation profile of the user. A valve mechanism couldthen be used to shut-off transfer or conveyance of the liquid or gelfrom the supply reservoir when the inhaler device is not in use, e.g.when it is switched off.

In some embodiments, the housing that accommodates the support bodyincludes one or more air inlets, such that air may be drawn in and mixedwith the vaporized substance as it is transformed to a vapour. The oneor more air inlets may direct air into the second heating zone, or mayalternatively be provided either upstream and/or downstream of thesecond heating zone. Thus, in a particular embodiment, the housing mayinclude a plurality of holes extending (e.g. radially) through a sidewall of the housing into each second heating cavity. The one or more airinlets or the inlet holes may serve to provide a balancing air-flow;i.e. to create a desired air-flow resistance for a user when the systemis incorporated in an inhaler device. Preferably, the one or more airinlets can be selectively changed or adjusted by a user, e.g. bymodifying an air inlet size, to regulate a mix of inlet air and theaerosol and/or vapour to be inhaled and to modify the flow resistance ofthe device.

According to a further aspect, the present invention provides an inhalerdevice, especially an electronic cigarette or a personal vaporizer, forgenerating an aerosol and/or vapor from a substance to be heated, suchas a liquid solution or a gel, wherein the inhaler device includes aheating system according to any one of the embodiments described above.

According to yet another aspect, the invention provides a method ofheating a substance, especially a liquid solution or a gel, in aninhaler device, such as an e-cigarette or a personal vaporizer, themethod comprising:

-   -   conveying the substance to be heated from a supply reservoir        through at least one supply channel by capillary action or        surface tension forces;    -   heating the substance in the at least one supply channel as the        substance is conveyed there-through.

In some embodiments of the invention, the step of heating the substancein the at least one supply channel is performed by one or moreelectrical heating element provided in each supply channel. As notedabove, each heating element may respectively comprise an electricalresistance element, such as a wire, ribbon, strip, foil, or a conductivecoating, for Joule heating or resistance heating. Each heating elementis therefore desirably powered by an electrical supply, such as abattery, in the inhaler device.

In some embodiments, the step of heating the substance in the at leastone supply channel is performed or carried out on a periodical orintermittent basis; for example, in a pulsed or in an alternatingmanner.

In some embodiments, the step of conveying the substance to be heatedfrom a supply reservoir through at least one supply channel involvesconveying the substance to a main heating zone for vaporization of thesubstance. In this way, the step of heating the substance in the atleast one supply channel as it is conveyed comprises a preheating of thesubstance in a first heating zone. The method of this embodimenttherefore includes the further step of heating the substance in the main(second) heating zone to form a vapor, which then typically condenses toform an aerosol. The step of heating the substance in the second heatingzone may also be performed by one or more electrical heating elements.

In some embodiments, each of the preheating and heating steps may becarried out periodically or sequentially. That is, each of the heatingzones may be activated or powered in an alternating or pulsed manner inspecific or predetermined activation intervals or periods. For example,an activation period of 50 msec could be applied to power or activateeach of the first heating elements for this period, followed by anactivation period of 50 msec for each second heating element. Such apulsed activation of the heating elements can provide improved energyconsumption.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the invention and the advantagesthereof, exemplary embodiments of the invention are explained in moredetail in the following description with reference to the accompanyingdrawing figures, in which like reference characters designate like partsand in which:

FIG. 1 is a schematic cross-sectioned side view of a heating system inan inhaler device according to an embodiment of the invention;

FIG. 2 is a schematic perspective view of part of a heating systemaccording to an embodiment of the invention; and

FIG. 3 is a schematic end view of that part of the heating system inFIG. 2;

FIG. 4 is a schematic partial cross-section view in the direction ofarrows IV-IV in FIG. 3;

FIG. 5 is a schematic perspective view of the heating system in theinhaler device of FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The accompanying drawings are included to provide a furtherunderstanding of the present invention and are incorporated in andconstitute a part of this specification. The drawings illustrateparticular embodiments of the invention and together with thedescription serve to explain the principles of the invention. Otherembodiments of the invention and many of the attendant advantages of theinvention will be readily appreciated as they become better understoodwith reference to the following detailed description.

It will be appreciated that common and/or well understood elements thatmay be useful or necessary in a commercially feasible embodiment are notnecessarily depicted in order to facilitate a more abstracted view ofthe embodiments. The elements of the drawings are not necessarilyillustrated to scale relative to each other. It will further beappreciated that certain actions and/or steps in an embodiment of amethod may be described or depicted in a particular order of occurrenceswhile those skilled in the art will understand that such specificitywith respect to sequence is not actually required. It will also beunderstood that the terms and expressions used in the presentspecification have the ordinary meaning as is accorded to such terms andexpressions with respect to their corresponding respective areas ofinquiry and study, except where specific meanings have otherwise beenset forth herein.

With reference to FIGS. 1 to 5 of the drawings, a part of an inhalerdevice 1 embodied as an electronic cigarette (also known as an“e-cigarette”) is represented schematically. This inhaler device 1includes a casing 2 provided in the form of a generally cylindricalsleeve, which accommodates a heating system 3 according to theinvention. The heating system 3 is designed for heating a liquidsolution or gel L supplied from a reservoir 4 in the inhaler device 1 togenerate an aerosol and/or vapor V for inhalation by a user as asubstitute for smoking traditional cigarettes. To this end, the liquid Lmay include a solution of propylene glycol, vegetable glycerin, aflavorant, and/or one or more flavours.

The heating system 3 of this embodiment provides two-step or two-stageheating of the liquid L to generate or produce the aerosol and/or vaporV for inhalation. In particular, with reference also to FIGS. 2 and 3 ofthe drawings, the heating system 3 includes a first heating zone 5 whichcomprises a plurality of supply channels 6 formed in and through a bodymember or plug member 7 having a generally cylindrical shape, and anumber of first heating elements 8 in the form of metal wires whichextend through each of the supply channels 6. As seen in FIG. 1, thisbody member 7 is optionally accommodated within a generally cylindricalhousing 9.

As seen in drawing FIGS. 2 and 3, the supply channels 6 are provided asfine bores or passages having a diameter in the range of about 0.1 mm to2.0 mm, preferably in the range of 0.1 mm to 1.0 mm (e.g. a diameter ofabout 0.5 mm), which are drilled to extend generally axially through thebody member 7 for conveying the liquid solution L from a supplyreservoir 4 by capillary action, i.e. by surface tension forces. Thebody member 7 itself in this case has a diameter φ of about 12 mm. Thecapillary channels 6 of the first heating zone 5 are configured toreceive the liquid L from the adjacent supply reservoir 4 via directcontact ensured by a feed mechanism 10 for delivering the liquid L inthe supply reservoir 4 to the first heating zone 5. In the present case,the feed mechanism applies pressure to the liquid L in the reservoir 4via a spring 11 which acts on a movable piston 12.

The heating elements 8 provided in this case are comprised of Nichrome80/20 wires which are joined or interconnected on a face of the bodymember 7 by conductive bridges 13. The wire heating elements 8 arepreferably arranged such that they are not in contact with the internalsurface of the channels 6, but rather extend freely (i.e. spaced fromthe internal surface) substantially centrally or along a longitudinalaxis of the channels 6, as seen in FIG. 4. This can advantageously limitor minimise the formation of deposits and residues in a channel 6 fromthe liquid L being heated. As an alternative, however, the first heatingelements 8 could also comprise conductive foil, e.g. molybdenum silicide(MoSi₂), deposited as a film over a surface of each channel 6.

Thus, the bridges 13 interconnecting the heating elements 8 conductelectric current to each of the wires 8 that extend through thecapillary bores 6, but do not themselves perform any heating. Theheating wires 8 are in intimate contact with the liquid L as it ispasses from the supply reservoir 4 through and along the supply channels6 by or under capillary action. These first heating elements or wires 8are provided with electrical energy from a battery 14 and are therebyheated when the inhaler device 1 is switched on or activated to effect apreheating of the liquid L in the first heating zone 5. As the liquid Lin the first heating zone 5 undergoes initial heating, it may begin toboil or at least expand and become pressurized, such that it istransferred or conveyed by both capillary action and by thermalexpansion to a second heating zone 15, as well as by the influence of aninflux of new liquid L into the first heating zone 5 or channels 6 fromthe reservoir 4. Thus, the liquid L is already preheated as it emergesfrom the channels 6 into a main heating chamber 16, which forms a mainor second heating zone 15 of the heating system 3 of the invention.

Thus, in this embodiment, the second heating zone 15 includes a heatingcavity 16 and at least one second heating element 18 for electricallyheating the liquid L when it enters the second heating zone. The secondheating element 18 in this example comprises a wire coil and, as withthe first heating elements 8, may again be formed from Nichrome 80/20wire. In any case, the second heating element 18 further heats thepreheated liquid L to effect its full vaporization in the chamber orcavity 16, in which gas formed by the vaporization of the liquid L mayexpand. For this reason , the second heating cavity 16 may terminate inor communicates with a nozzle 19 at an end face of body member 7,through which the vapor V is emitted into a vapor chamber 20 from whichthe user may inhale that aerosol and/or vapour V via a mouthpiece (notshown) of the inhaler device 1. Optionally, a foil 21 with multiplemicro-openings or holes may be provided over an end region of the bodymember 7 and housing 9 facing vapor chamber 20. This foil 21 may, forexample, form a filter membrane for the aerosol and vapor V emitted fromthe heating system 3. At the same time, the foil 21 may provide air-flowresistance, whereby a pressure difference develops across the array andthe gas emitted undergoes an expansion and vapour-phase cooling to forminhalable aerosol droplets.

As is also apparent from FIG. 1 of the drawings, radial air inlets 22may be provided through the side wall 8 of the housing 9 into the secondheating cavity 16 to enable the influx and mixture of air with thevapour V in the second heating zone 15. This may assist with ensuringthat a proper flavour or concentration balance is provided in theaerosol and/or vapor V produced. Furthermore, the radial inlets 22 maybe used to balance the airflow through the device to provide a desiredairflow resistance or “inhalation feel” for the user. Also, this mayassist to cool the aerosol or vapour V before it reaches the user via amouthpiece of the inhaler device 1. It will be noted that air inlets mayalso be provided downstream of the nozzles 19, e.g. in the vapor chamber20, to balance or control the flow. With reference to FIG. 5, forexample, it will be seen that air inlets 22 may be provided openingradially into the vapor chamber 20 downstream of the second heating zone15, instead of (or in addition to) into the second heating cavity 17directly.

It will be noted that cylindrical body member 7 is desirably comprisedof a ceramic material that is pre-machined or fabricated to form thesupply channels 6 providing the fluid communication between the supplyreservoir 4 and the second heating zone 15. As the ceramic body member 7also supports the first and second electrical heating elements 8, 18,the electrical insulating properties of the ceramic material arerelevant to a desired and proper functioning of this heating system 3.

It will also be noted that the heating system 3 shown in this embodimentmay optionally be provided in a cartridge designed to be inserted intothe casing 2 of the inhaler device 1. That is, the housing 9incorporating the supply reservoir 4 of the liquid L and the heatingsystem 3 described above may be provided as a replaceable (e.g.disposable) cartridge, so that once the supply reservoir 4 of the liquidL to be heated is depleted or exhausted, that cartridge may be removedand a replacement cartridge may then be inserted into the casing 2 ofthe inhaler device 1 in its place. The depleted cartridge could theneither be re-filled with liquid L to be used again or simply disposedof.

Although specific embodiments of the invention have been illustrated anddescribed herein, it will be appreciated by those of ordinary skill inthe art that a variety of alternate and/or equivalent implementationsexist. It should be appreciated that the exemplary embodiment orexemplary embodiments are only examples, and are not intended to limitthe scope, applicability, or configuration in any way. Rather, theforegoing summary and detailed description will provide those skilled inthe art with a convenient road map for implementing at least oneexemplary embodiment, it being understood that various changes may bemade in the function and arrangement of elements described in anexemplary embodiment without departing from the scope as set forth inthe appended claims and their legal equivalents. Generally, thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein.

Also, it will be appreciated that in this document, the terms“comprise”, “comprising”, “include”, “including”, “contain”,“containing”, “have”, “having”, and any variations thereof, are intendedto be understood in an inclusive (i.e. non-exclusive) sense, such thatthe process, method, device, apparatus or system described herein is notlimited to those features or parts or elements or steps recited but mayinclude other elements, features, parts or steps not expressly listed orinherent to such process, method, article, or apparatus. Furthermore,the terms “a” and an used herein are intended to be understood asmeaning one or more unless explicitly stated otherwise. Moreover, theterms “first”, “second”, “third”, etc. are used merely as labels, andare not intended to impose numerical requirements on or to establish acertain ranking of importance of their objects.

What is claimed is:
 1. A heating system for an inhaler device forgenerating an aerosol and/or a vapor from a substance to be heated, thesystem comprising: at least one supply channel for conveying a substanceto be heated from a supply reservoir under capillary action or surfacetension forces within the at least one channel; and heating meansconfigured to heat the substance as it is conveyed through the at leastone channel.
 2. The heating system of claim 1, wherein the heating meanscomprises at least one first heating element provided within the supplychannel, the first heating element preferably extending along a lengthof the supply channel.
 3. The heating system of claim 2, wherein the atleast one first heating element includes one or more of an electricallyconductive wire, strip, foil, or conductive coating in the at least onesupply channel; the foil or conductive coating preferably forming alayer or coating on an inner surface of the at least one supply channel.4. The heating system of claim 1, comprising a plurality of supplychannels for conveying the substance to be heated under capillary actionor surface tension forces; wherein the heating means is configured toheat the substance as it is conveyed through each supply channel; andwherein the plurality of supply channels and the heating means togetherdefine a first heating zone for the substance to be heated.
 5. Theheating system of claim 1, wherein the at least one supply channel isformed in a periphery of, and/or through, a body member which separatesthe supply reservoir from a vapor chamber from which the aerosol and/orvapor is inhaled.
 6. The heating system of claim 5, wherein the heatingelements are interconnected by electrically conductive bridge elementsprovided in or on the said body member.
 7. The heating system of claim5, wherein the body member separates the supply reservoir from a secondheating zone for vaporization of the substance; wherein the at least onesupply channel is configured to convey the substance to the secondheating zone and preferably extends axially of the body member.
 8. Theheating system of claim 7, wherein the second heating zone includes oneor more second heating cavity, and wherein at least one of the supplychannels is in fluid communication with a respective second heatingcavity.
 9. The heating system of claim 1, wherein the at least onesupply channel has a diameter in the range of 0.1 to 2.0 mm, preferablyin the range of 0.1 to 1.0 mm.
 10. The heating system of claim 1,further comprising a housing that accommodates the supply reservoir forthe substance to be heated, and a body member that separates the supplyreservoir from a second heating zone and provides fluid communicationthere-between via the at least one supply channel.
 11. The heatingsystem of claim 1, further comprising a feed mechanism configured todeliver the substance to be heated from the supply reservoir; whereinthe feed mechanism preferably generates fluid pressure in the supplyreservoir.
 12. An inhaler device, such as an electronic cigarette or apersonal vaporizer, for producing aerosol and/or vapor from a substanceto be heated, especially a liquid or a gel, wherein the inhaler deviceincludes a heating system, the heating system comprising: at least onesupply channel for conveying a substance to be heated from a supplyreservoir under capillary action or surface tension forces within the atleast one channel; and heating means configured to heat the substance asit is conveyed through the at least one channel.
 13. A method of heatinga substance, especially a liquid or gel, in an inhaler device, such asan e-cigarette or a personal vaporizer, the method comprising: conveyingthe substance to be heated from a supply reservoir through at least onesupply channel by capillary action or surface tension forces; heatingthe substance in the at least one supply channel as the substance isconveyed there-through.
 14. The method of claim 13, wherein the step ofheating the substance is performed by one or more electrical heatingelement provided in each supply channel.
 15. The method of claim 13,wherein the step of heating the substance in the at least one supplychannel is carried out on a periodical or intermittent basis, desirablyin a pulsed or alternating manner.